The present invention relates to heat sink devices for use in electronic devices, for example, to those for releasing the heat generated by CPU assemblies in desktop electronic devices to outside the housing.
In order to release the heat generated by CPU assemblies disposed in the housings of electronic devices to outside the housing, a heat sink, for example, of aluminum is conventionally attached to the CPU assembly. For example, Japanese Utility Model Registration No. 3054704 discloses a known device for connecting the heat sink to the CPU assembly.
Conventional heat sink devices for use in electronic devices include fastening members for connecting the heat sink to the CPU assembly. However, these fastening members are complicated in shape and low in fastening strength. Further a space portion of predetermined width is conventionally formed in the radiating finned surface of the heat sink for fitting the fastening member therein. The provision of the space portion therefore entails the problem of correspondingly reducing the number or size of radiating fins to result in a lower radiation efficiency. The conventional fastening member has at one end thereof a portion inserted through holes in the heat sink and the CPU assembly and fixed in place by being bent at its outer end projecting outward beyond the outer surface of the CPU assembly. Accordingly, connecting the heat sink to the CPU assembly requires a cumbersome procedure. Further because the inserted portion of the conventional fastening member usually has a width of about 5 mm, the hole in the CPU assembly must be as large as at least 6 mm in diameter. This entails the problem that the CPU circuit board needs a corresponding larger space for drilling such holes, hence a disadvantage in design. It is desired that the holes to be formed in the circuit board of the CPU assembly, the heat sink, etc. be as small as possible. Preferable are, for example, holes having a diameter of up to 3 mm.